PTT services, also known as walkie-talkie or dispatch services, provide near-instant, half-duplex communication between a PTT caller and one or more target PTT users. PTT services are typically offered as a subscription service on a wireless communications system, which may also offer interconnect, short message service (SMS), packet data and other communications services to its subscribers. Each wireless communications system facilitates communications using one or more wireless technologies such as CDMA, global system for mobile communication (GSM) or time division multiple access (TDMA). Known PTT technologies include Nextel's Direct Connect®, Qualcomm's QChat and Push-to-Talk over Cellular (PoC).
A PTT call spanning more than one PTT network or technology may be connected through one or more gateways that translate between signaling and media protocols of the networks. For example, a High Performance PTT (HPPTT) CDMA network (e.g., QChat) includes a plurality of interoperability gateways adapted to receive PTT call requests from an external PTT network, such as an Integrated Digital Enhanced Network (iDEN network). A PTT call from a subscriber on an iDEN network to a target subscriber on a conventional HPPTT network may be forwarded to any interoperability gateway on the HPPTT network. The gateway forwards the call to a regional HPPTT Server which manages the PTT call within the HPPTT network.
The target subscriber, however, may be located in a remote region, resulting in inefficient PTT call handling between the HPPTT network and the external PTT network. For example, a PTT call intended for a HPPTT subscriber roaming in New York may be routed to a HPPTT network interoperability gateway in California, and the HPPTT Server in California will be responsible for establishing the PTT call with the HPPTT target roaming in New York, resulting in a cross country PTT call. There is a need for an efficient system and method for handling PTT calls from an external system where the PTT targets are located in a HPPTT network.